An investigation of the pulsed characteristics of high-voltage silicon carbide diodes

Pulsed alternators and capacitor banks are the two primary energy storage mechanisms used to power very high current loads with pulse lengths on the order of several milliseconds. Both of these sources require switches capable of conducting megamperes of current and operating at voltages on the order of several kilovolts. Switch modules can be constructed using solid-state silicon switches in large series/parallel arrangements, but these modules make up a considerable portion of the mass and volume of the pulsed power system. In an effort to reduce the size of the pulsed power systems, it has been proposed that the superior electrical and mechanical properties of silicon carbide (SiC) will result in mass and volume savings in the range of up to 60 percent for systems with the high-current Silicon (Si) devices replaced with SiC devices. Experimental testing of 4H-SiC PiN high-voltage diodes is being conducted at the University of Texas at Austin´s Institute for Advanced Technology to investigate the capabilities of SiC as a semiconductor device material in pulsed power applications. This paper describes testing of 1-mm, 2-mm, 3-mm, and 6-mm square PiN diodes fabricated by CREE, Inc. with epitaxial layers of 90/spl mu/m, 120/spl mu/m, and 150/spl mu/m.